Well-casing perforator.



A. C. GRAHAM.

WELL GASING PERFORATOR.

APPLIOATION FILED MAR. 5. 191s.

Patented Aug. 12,1913.

Imi,

.illfl WTNESSES 4 @MQW imm' ,4 TTURNEYS ALBERT CLARENCE GRAHAM, 0F OILFIELDS, CALIFORNIA.

WELL-CASING PERFORATOR.

Specieation of Letters Patent.

Patented Aug. 12,1913.

Application filed Hatch 5, 1913. Serial-I0. 752,069.

To all whom t may concern.'

Be it known that I, ALBERT C. GRAHAM, a citizen of the United States, and a resident of Oilfields, in the county of Fresno and State of California, have invented a new and Improved Well-Casing Perforator, of which the following is a full, clear, and eX- act description.

This invention relates to an apparatus for perforating casings for deep Wells, the perforating device being of that type 4disclosed in my co-pending application 747,923 and in which rotary perforating wheels are em.- ployed to produce a plurality of rows of perforations longitudinally of the well casing during movement of the perforator in one direction.

The invention has for one of its objects to improve and simplify the construction and operation of devices of this character'so as to be comparatively simple and inexpensive to manufacture, reliable and efficient in use, and so `designed as to require a minimum of power to operate.

Another object of the invention is the provision of a novel arrangement of elevators between adjacent perforating wheels, whereby the movement of one wheel t0 perforating position effects corresponding movement of the other wheel, said adjacent wheels being disposed in different planes so as to make separate rows of perforations.

Another object of the invention is the employment of anti-friction devices in the body of the perforator, which devices are so located with respect to the lateral thrust of the perforating wheels as to minimize the friction between the perforator and the well easing.

lVith these objects in view and others as will appear as the description proceeds, the invention comprises various novel features of construction and arrangement of parts which will be more fully described hereinafter and set forth with part-icularity in the claims appended hereto.

In the accompanying drawings, wherein similar reference characters are employed to designate corresponding parts, Figure 1 is aside view of the perforator` with the perforating Wheels shown in retracted or indrawn position; Fig. 2 is an enlarged sectional view showing theposition of the perforator in a Well casing; Fig. 3 is a sectional view showing perforating wheels projected.

to perforating position; Fig. 4 is a perspective view of one of the elevators between adjacent perforating wheels; Fig. 5 is a sectional view on the line 5-5 ofFig. 2; Figs. I

6 and 7 are end views of perforators for Inakmg four and three rows of perforations respectively; the well casing being shown in section; and Fig. 8 is an enlarged detail sectional view on the line 8-8 of F ig. 1.

Referring to the drawings, Aidesignates the body of the perforator, which body is in the form of a bar of suitable length and having at its upper end a threaded stem l for connection with the rod of the drilling mach-ine. The body A of the perforator is provided with chambers 2 which contain perforating Wheels 3. Each chamber has its opposite walls formed with parallel slots 4 that are inclined to the axis of the perforator body A, and into these slots extend the journals 5 of the perforating wheels. Adjacent wheels are located with their axes at right-angles to each other in the form .shown in Fig. 2, whereas in the form shown 1n Fig. 7 the wheels are disposed in planes 120 apart. As shown in Fig. 5, the perforating wheels 3 are formed with hubs 6 of substantial size so as to be engaged by the heads of the elevators B. As shown in Fig. 4.1, each elevator consist-s of a shank or stem 7 with Ushaped heads 8, these heads being arranged at right-angles to each other to correspond to the relative position of the adjacent perforating wheels 3. lThe teethv 9 of the perforating wheels enter between the flanges 10- of the heads 8, .and the edges of these flanges bear against the'hubs 6 of the wheels. The Shanks or stems 7 slidably eX- tend through openings 1l formed in the body of the perforator between adjacent chambers 2.

The elevator for the bottom perforating wheel comprises a rod 12 which has at its upper end a head 13 similar to the heads of the form of elevator shown in Fig. 4." This rod, which extends downwardly from the body A of the perforator, is slidable in the opening 14, and on the lower end of the rod is carried a shoe or combined guide and anchoring device C, which is composed of a plurality of bowed springs 15 connected to collars 16 through which the rod 12 slides, there being on the lower end of the rod 12 a stop or head 17 so as to retain the device C attached to the perforator. At the lower end of the rod 12 and slightly above the head 17 is a pivoted catch 18 which is adapted to engage the lower collar 16 of the device C, to hold the rod 12 fixed with relation to the device C during the act of perforating; the well casing, as will be more fully described hereinafter.

To reduce friction between the perforator and the well casing during the perforating operation, which friction results from the lateral thrust due to the perforating wheels, a plurality of anti-friction devices are employed, said devices being. in the form of annular sets of balls D, which are arranged spaced distances throughout the length of the body A and extend circumferentially thereof. Particularly, there is a set of antifriction balls above and below each perforating wheel, so that in lthe four-wheeled type shown in Figs. 1 and 2 there are five sets of anti-friction balls. The races 19 are undercut as shown by dotted line in Fig. 1, and the balls project partly out of the races. Extending upwardly from each race is an entering pocket 20, whereby the balls are dropped into each race one by one. Since the entering pocket extends upwardly yfrom the races there .is no danger of the balls dropping out.

In operation, the perforator is entered intoi the well casing E while the wheels 3 are in the position shown in Fig. 2. The wheels will remain in this position by reason of their own weight, and they can only be projected to perforating position by the operation of the elevators. During the downward movement of the tool into the casing the shoe C, by reason of its frictional engagement with the casing, will engage the lowei` end of the perforator body A and be pushed downwardly thereby. When the tool has reached the position where the perforations are desired an upward movement is exerted on the tool, and thereby the body A with the rod 12 is raised while the shoe C remains f or the time being stationary, by its frictionalengagement with the well casing. During this upward movement of the rod 12 the catch 18 passes iip-wardlythrough the lower collar 16 of the shoe C unt-il it .will engage the said collar, as shown in Fig. 3. A downward movement is now imparted to thetool, and as a result the body A has an initial movement independently of the rod 12, which is held stationary by the device C. At 'this time the lower perforating wheel is'raised and projected laterally by the inclination of the slots 4.' This lower wheel lopera-tes on the next wheel through the intermediate elevator B to project such wheel to perforating position, and in this manner the wheels are all thrown to Vposition where they will pe-rforate thel casing as the tool is forced downwardly. During this downward movement the drag of the shoe C will inf/dese bei suilicient to maintain the wheels projected to perforating position. After the pipe has thus been perforated the desired length the tool is withdrawn or lifted by the well rigging, and during this operatio-n the perforating wheels will gravitate in operative position. I

Fromthe foregoing description taken in connection with the accompanyin drawings the advantages of the method og operation and of the apparatus shown will be readily understood by those skilled in the art to which the invention appertains, and while l have described the apparatus which l" novir consider to be the best embodiment thereof, I desire to have it understood that the apparatus shown' is merely illustrative, and that such changes may be made when desired as are within the scope of the appended claims.

Having thus described my invention, l claim as new and desire to secure by Letters Patent:

1. Alwell casing perforating device comprising a body, perforating wheels mounted thereon and arranged, with their axes at an angle to each other, and an elevator between the wheels, said elevator having terminal heads disposed at an angle to each other for engaging the hubs of ,the respective wheels and spanning t-he teeth thereof. r

2. A well casing perforator comprising a body having chambers one above another and arranged in different planes, the opposite walls of the chambers having inclined slots, perforating wheels disposed in the chambers and having journals engaging in the slots thereof, means engaging the lower wheel for elevating the same', and an elevator between the wheels and having heads disposed at an angle to each other for engaging the hubs of the wheels.

3. A well casingperforator comprising a body provided with chambers one above the other, a perforating wheel :in each chamber, the wheel of one chamber being disposed at an angle to the wheel inthe other chamber, an elevator between the wheels whereby upward movement of" the lower wheel produces corresponding movement of the upper wheel, anti-friction devices extending entirely around the body and carried thereby at a point between the wheels, and additional anti-friction devices' extending en-- tirely around the body and carried thereby at a point above the'upper Wheel and at a point below the lower wheel.

In testimony whereof I have signed my name to this 'specification in the presence of two subscribing witnesses.

ALBERT CLARENCE GRAHAM.

Witnesses:

D. A. Rrmm'rz, J. RAY CARSON. 

